Overdrive download notifications don't go away

I recently used Overdrive Media Player to download audioclips for audiobooks I was browsing from my local online library. The clips downloaded fine, however, when I turn on my Playbook or come out of sleep mode, the download notifications often appear (the exclamation mark in the upper left hand corner of the home screen) indicating my downloads are completed. I close these notofications regularly but they continue to reappear. This has gone on for about a week. I can use Overdrive to read books, browse and download other books, etc.... without any other issues, nor does it happen for other downloads.

Does anyone have any experience or solution for this problem? Thanks in advance for any advice or assistance offered.

Directions- thanks to SifJar and Yadadi:
"I fixed my notifications by installing ghost commander from app world, then in the left pane chose apps, then found the downloads app, then chose "shortcuts" tapped the shortcut that appeared, launching the downloads app. From there I deleted the failed downloads and the notifications have stopped now. No need to uninstall any apps, unless they keep retrying the downloads even after deleting them manually.

Thanks for the idea
I have had strange notifications for downloads relating to the GOweather app. I had deleted the app some time ago.
Ghost Commander was the only file manager which showed the directory where the problem downloads were located. I deleted them and hopefully the notification will disappear.